If its for any software then without looking at video I can guess it would be changing of your system date.

Time trials are more sophisticated than that. They'll usually work with registry entries and miscellaneous hidden files to keep track of time by themselves.
Most time trial cracking techniques deal with disassembling the program and bypassing or short circuiting the jump that is triggered by the time expiring. I haven't checked out the video yet... looking forward to watching it, though.